This invention relates to a tubular structural component which is thermally stressed in service and which, by means of a septum, is separated into several flow passages or the like. Such a component may find application particularly in the outlet zone of an exhaust manifold which forms part of the exhaust system of an internal combustion engine.
In order to improve the engine performance of internal combustion engines, it is conventional to use multi-passage pipes (that is, pipes which have exhaust channels separated from one another) in the exhaust system, at least in the zone adjacent the exhaust manifold. The outlet portion of the exhaust manifold itself is, in such cases, designed as a multi-channel component; the septum in the exhaust manifold and the septum in the adjoining exhaust pipe are in alignment with one another. Frequently, the connection between the exhaust manifold and the exhaust pipe is designed as an articulated joint, wherein the exhaust manifold is provided with a cylindrical sealing flange to which the exhaust pipe is secured by means of a bowl-shaped terminus with the interposition of a heat-resistant sealing ring. By virtue of this coupling structure oscillations and vibrations occurring during operation may be taken up.
During the operation of the internal combustion engine the exhaust manifold and the exhaust pipe are exposed to hot exhaust gases whose temperature may reach approximately 900.degree. C. The septum of the exhaust manifold which is exposed to the hot exhaust gases on both sides is heated to a substantially greater extent than the outer wall of the exhaust manifold which, in addition, is better cooled, particularly by air streams generated during vehicle travel. Thus, the septum which expands to a greater extent due to heating, risks to deform the originally circular sealing flange of the exhaust manifold, that is, it may exert such a pressure on the flange that the latter assumes a cross-sectionally oval configuration. As a result of this occurrence a satisfactory sealing effect between the sealing flange and the sealing ring can no longer be ensured.